DESCRIPTION: (Applicant's Abstract) The long-term goal of this Stage I therapy development project is to reduce drug abuse and its negative consequences in persons with co-occurring schizophrenia. Persons diagnosed with both schizophrenia and a drug use disorder experience substantial dysfunction and poor treatment outcomes. Most receive treatment in the mental health system and do not acknowledge drug abuse as a problem. The Transtheoretical Model of Change, along with recent advances in motivational interventions, provides a useful framework to understand and change drug abuse in this context. The proposed research will occur in three phases. First, we will conduct formative research to guide the adaptation of assessment and intervention materials for use with persons with schizophrenia. Second, we will evaluate the reliability and validity of two theoretically important measures (readiness-to-change, decisional balance) in a sample of 100 outpatients with schizophrenia; these instruments will serve as the primary change measures in the pilot test of the motivational intervention. Third, we will develop and evaluate the feasibility of a brief motivational intervention intended to enhance readiness for drug abuse treatment. Twenty outpatients with DSM-IV diagnoses of schizophrenia and drug abuse or dependence will receive an individualized motivational intervention, designed to supplement their ongoing psychiatric treatment. Assessments at pre- and post-treatment and at a 12-week follow-up will evaluate therapy acceptability, readiness-to-change, psychiatric status, drug use, treatment involvement, and HIV risk behaviors. We predict that participants receiving the motivational intervention will increase their readiness to engage in drug abuse treatment and their perception of the advantages of reducing drug use, and decrease their perception of the disadvantages of such change. Exploratory analyses will evaluate the effects of the motivational intervention on treatment involvement, HIV risk behavior, and drug use.